ADRENAL OR SUPRARENAL GLANDS (GLANDS OF EMERGENCY) -

• These are paired structures located on the top of the kidneys.
• Each adrenal gland has two parts external adrenal cortex and internal adrenal medulla.
• The adrenal cortex is derived from the mesoderm of the embryo & adrenal medulla from the ectoderm.
• The cortex is surrounded by a fibrous capsule.
• The adrenal cortex is differentiated into three regions or zones -

             (i) Outer, thin zona glomerulosa (15% of the gland)

             (ii) Middle, thick zona fasciculata (50% of the gland)

             (iii) Inner, thin zona reticularis (7% of the gland).

• The cells of the zona fasciculata and zona reticularis contain vitamin C (ascorbic acid).